Reality is created by Seer Systems, who created the WaveSynth/WaveGuide software that came with the AWE64. It is based on this technology, but is far more powerful. It supports 4 methods of synthesis: SondiusŪ waveguide synthesis, FM, analog and modal, as well as allowing sampled sounds. Waveguide synthesis is a type of physical modelling (it is used in the Yamaha VL70m, VL7 and VL1). The analog model support 4 oscillators, 4 LFOs, 4 filters and 4 envelopes. Modal synthesis is a way of generating mallet and bell instruments using a bank of coupled, resonating filters. Reality is unique among the synthesizers here in that it comes with over 450 sounds including a lot of samples, rather than just presets. It is meant to be able to function as an almost complete sound source - producing sounds from sampled pianos to analogue-style leads.
With all these features I was expecting amazing results. What I have got out of it didn't greatly impress me, but Reality has a very strong following, so don't take my word on that. Reality used to only work with Creative Labs soundcards, however its support has been greatly expanded. The number of voices Reality can do at once depends on the complexity of the sounds and the power of the computer. For example a P2/266 can do 73 sounds at 44KHz if the sounds have 2 oscillators and 1 filter. Reality costs $495.